hideall = { \hide NoteHead \hide Stem \hide Rest \hide Accidental \hide Tie \override NoteHead.no-ledgers = ##t \hide Dots }
showall = { \undo \hide NoteHead \undo \hide Stem \undo \hide Rest \undo \hide Accidental \undo \hide Tie \undo \override NoteHead.no-ledgers = ##t \undo \hide Dots }

